1. Field of the Invention
This invention relates to the field of fiber optic devices and, more particularly, relates to an assembly and a method for fabricating the assembly for forming a plurality of optical couplers in an integrated fixture.
2. Description of the Prior Art
The use of optical fibers--so-called "light pipes"--has progressed in a relatively few years from laboratory curiosities to sophisticated optical communications and data transmission systems. The fibers function by transmitting light longitudinally along their flexible axis and are made of various materials having differing properties which are selected for specific uses.
Fiber optic couplers are well known to the art and generally involve the connection between two fibers by merging, fixing or otherwise combining the fibers along a common section. See for example: Barnoski et al, U.S. Pat. No. 4,054,366; McMahon, U.S. Pat. No. 4,021,097; Auracher et al, U.S. Pat. No. 4,089,583.
In considering fiber optic couplers, there is a basic distinction between unidirectional and bidirectional couplers. The unidirectional, or launch, couplers are three-port devices having optional fiber connections at each port. One of these ports is the input to the launch fiber, and the other two ports are opposite ends of a common fiber called the throughput fiber. One particularly effective launch coupler is disclosed in our co-pending application Ser. No. 123,034, filed Feb. 20, 1980 now U.S. Pat. No. 4,307,933.
Although end-to-end coupling devices for a plurality of fiber optics have been developed using a variety of differing approaches, including grooved block assemblies (see for example: Rocton, U.S. Pat. No. 4,079,927; Gauthier, U.S. Pat. No. 4,148,559; Cherin et al, U.S. Pat. No. 3,912,574; and Auracher et al, U.S. Pat. No. 4,111,522), no known prior art discloses an assembly for accommodating a large number of optical fiber couplers. In fact, most prior art couplers involve a relatively small number of fibers encased within a coupling package and are incapable of providing for a large number of independent optical couplers. Examples of these types of couplers and packages are shown in Milton, U.S. Pat. No. 3,933,410; Kao et al, U.S. Pat. No. 4,087,156; Gerndt, U.S. Pat. No. 4,113,345; Suzaki, U.S. Pat. No. 4,136,929; Dyott, U.S. Pat. No. 4,135,780; Tachiba, Japanese Pat. No. 52-24539; Serizawa, Japanese Pat. No. 54-118255; and Tsujimoto et al, "Fabrication of Low-Loss 3 dB Couplers with Multimode Optical Fibers", Electronics L., Vol. 14, No. 5, March, 1978, pages 157-8.
There is a definite need, therefore, for an assembly which is capable of forming and providing for a large number of independent optical coupling devices, which assembly can be easily made and still meet the demanding optical tolerances required by such couplers.